The present invention relates to a leveller bar for a coke oven block.
A leveller bar for leveling the coal heap formed during the charging process under the charging holes of the oven compartment of the coke oven block is known. This leveller bar comprises two vertical plates connected with each other and spaced parallel from each other depending on the width of the oven compartment. In the intervening space between the plates several transverse coal deflecting and/or entraining devices are positioned behind each other.
The leveller bars used for leveling the coal chute cone formed during the charging process in the oven compartment, which are moved back and forth mechanically, should have the simplest, but also a durable, structure. Therefore, up to now leveller bars have been used, in which the so-called coal deflecting and/or entraining devices were formed in the shape of cross plates, which are welded at right angles to the vertical plates and connected simultaneously with each other. That means that the deflecting and/or entraining devices extend in this case over the entire width of the intervening space between the vertical plates. The number and the spacing of the coal deflecting and/or entraining devices is dependent on the number and spacing of the charging holes in the oven compartment and on the horizontal motion of the leveller bar.
Known leveller bars of the above-described type are generally adequate. The coal charging car either is equipped with a charging gas exhaust and dedusting device or stationary gas exhaust and dedusting devices are installed in the coke oven block, which exhaust the charging gases during the charging process vertically through the charging holes and conduct the cleaning.
Both according to the current legal requirements (TA Air) in the Federal Republic of Germany and also the new international legal Rules the charging gas should no longer be drawn through the charging holes, but as much as possible it should be conducted through the ascension pipe into the gas collecting main. Moreover a pump or fan device is to be installed in the ascension pipe, for example, a steam or power water pump, which can produce a low pressure in the oven compartment. With this changed type of charging gas exhaust, the coal charging car must be equipped with a so-called telescoping sealing device, which closes against the charging hole frame making a tight seal. As long as the coal heap has not reached the gas collection chamber in the oven compartment, the charging gas can flow to the gas collecting main comparatively unhindered, also when the conventional leveller bar structure is present. This situation changes however, as soon as the coal heap reaches the lower leveller bar edges, which means when the leveling process begins. Then the horizontal flow of the charging gas to the gas collecting main through the coal deflection and entraining devices, which extend across the entire width of the leveller bar, is strongly hindered. The deflection and entraining devices at certain positions of the leveller bar provide that the free flow of charging gas is partitioned and controlled correctly. Since the charging gas can reach the gas collecting main in all cases through the remaining narrow gap between the leveller bar and the walls of the oven compartment under great difficulty, this leads of necessity to a higher pressure in the oven compartment. The sealing at the charging hole frame cannot withstand this increased pressure. Thus a rather more or less strong uncontrolled emission occurs at the charging hole frame, which naturally is completely undesirable in the interests of maintaining air quality. The pump or fan device installed in the ascension pipes could take care of this emission in all cases with a high efficiency. However that solution leads understandably to high installation and operating cost.